Update from July Precision Teaching blogs
Hello Bloggerites,
Well tragedy stuck my computer and my most recent file became corrupted for this blog. That means I lost the files for July but did archive some of the talk back comments. I will more diligently back up my files (but I have a mac and bad things rarely happen to my computer or files :)
Well let’s get to task this month!
I hope to explain the following in my next series of entries. How to analyze graphic data on an SCC ala Parsonson and Baer (1978). Parsonson and Baer cover the following characteristics of visual analysis:
Stability of baseline
Variability within phases
Variability between phases
Overlap between data of adjacent phases
Number of data points in each phase
Changes in trend within phases
Changes in trend between adjacent phases
Changes in level between phases
Analysis of data across similar phases
Evaluation of the overall pattern of the data
Let’s start with Stability of baseline. Three main points to consider.
1. When baseline data drift in the direction of the intervention it is difficult to analyze claims of the intervention. Though with SCC you could make better judgments as when this occurs - by comparing celerations. But this logic varies from the steady state logic advocated by some.
2 and 3. Stable baselines or baselines in the opposite direction of the intervention help determine change is attributed to the intervention.
Each one of these situations appears in the chart below.
As you can see, analyzing baselines on the SCC offers the advantage of calculating a celeration as well as fairly portraying the trend.
